The data collection for the protocol started on 07/24/2006. Data has been collected from 65 patients with cerebral palsy and 12 non-disabled subjects.[unreadable] A standardized clinical evaluation form was developed through collaboration with Dr. Jean-Michel Gracies and Dr. Katharine Alter. The data collection procedures have been tested and refined. The original codes for data analyses originally developed by M. Lebiedowska have been refined by LaKisha Guinn, and the summer BESIP students. The codes have been tested and successfully applied to analyze biomechanical data from the popular clinical tests (popliteal angle test and pendulum test). We found that hamstring muscle hypertonia is commonly present during the popliteal angle test. We have made progress in developing a mathematical model of the pendulum test that is more precise than existing models. The preliminary analysis of the model strongly suggests that hypertonia, as detected during pendulum test, may be used as one of the main predictors of movement constrains during walking.